Knockback.js骨干集合只向UI添加第一个元素

时间:2013-05-23 13:41:53

标签: javascript jquery knockout.js backbone.js-collections knockback.js

我正在尝试用Knockback.js设置一些新东西,而现在我遇到了淘汰/敲击整合的问题。问题是,我已成功编写了一个事件处理程序,它将一个新模型添加到Objectives集合中,但UI只注册并添加了第一个这样的添加。它确实成功地将新目标添加到列表中,但只是第一个 - 在此之后,当集合成功地将新模型添加到列表中时,它不会出现在UI中。

<a class="btn" id="click">Click me!</a>
<div id="objectives" data-bind="foreach: objectives">
    <h3 data-bind="text: name"></h3>
</div>

这个脚本:

// Knockback script MUST be located at bottom of the page
$(document).ready(new function() {
// instantiate the router and start listening for URL changes
var page_router = new PageRouter();
Backbone.history.start();

// Get JSON value
var objectives;
$.getJSON('json.php', {table: 'objectives'}).done(function(data) {
    objectives = new ObjectiveCollection(data);
    var view_model = {
        objectives: kb.collectionObservable(objectives, {view_model: kb.ViewModel})
    };
    ko.applyBindings(view_model, $('#objectives').get(0));
});
$('#click').click(function() {
    var objective_model = new Objective({category: 3, name: Math.random(), descriptor: 'What up'});
    objectives.add(objective_model);
    console.log(objectives);
});
});

这里只显示了自定义模型:

/**
 *  Objectives model
 */
var Objective = Backbone.Model.extend({
// Defaults
defaults: {
    id: null,
    category: null,
    weight: null,
    name: null,
    descriptor: null
},
// Url to pass to
url : function() {
    // Important! It's got to know where to send its REST calls. 
    // In this case, POST to '/donuts' and PUT to '/donuts/:id'
    return this.id ? '/objectives/' + this.id : '/objectives'; 
}

});
/**
 *  Basic objectives collection
 */
var ObjectiveCollection = Backbone.Collection.extend({
    model: Objective,
initialize: function(models,options) {}
});

1 个答案:

答案 0 :(得分:2)

原来,问题出在这里:

var Objective = Backbone.Model.extend({
  // Defaults
  defaults: {
    id: null,
    category: null,
    weight: null,
    name: null,
    descriptor: null
}

它一直生成ID为null的模型,程序只显示具有唯一ID的对象。由于ID默认为null,因此它会将没有定义ID的两个对象视为相同。通过擦除id:null;一句话,这个问题就不再是一个问题了。